元組是不同類型的值的集合。 元組使用括號構造 (), 每個元組本身是類型簽名值 (T1, T2, ...), 這裏 T1, T2 是其成員的類型。 函數可以使用元組返回多個值,元組可以包含任意數量的值。

// Tuples can be used as function arguments and as return values
fn reverse(pair: (i32, bool)) -> (bool, i32) {
// `let` can be used to bind the members of a tuple to variables
let (integer, boolean) = pair;

(boolean, integer)


fn main() {
// A tuple with a bunch of different types
let long_tuple = (1u8, 2u16, 3u32, 4u64,
-1i8, -2i16, -3i32, -4i64,
0.1f32, 0.2f64,
'a', true);

// Values can be extracted from the tuple using tuple indexing
println!("long tuple first value: {}", long\_tuple.0);
println!("long tuple second value: {}", long\_tuple.1);

// Tuples can be tuple members
let tuple\_of\_tuples = ((1u8, 2u16, 2u32), (4u64, -1i8), -2i16);

// Tuples are printable
println!("tuple of tuples: {:?}", tuple\_of\_tuples);

let pair = (1, true);
println!("pair is {:?}", pair);

println!("the reversed pair is {:?}", reverse(pair));

// To create one element tuples, the comma is required to tell them apart
// from a literal surrounded by parentheses
println!("one element tuple: {:?}", (5u32,));
println!("just an integer: {:?}", (5u32));